Split BrowserThread into public API and private implementation, step 1.

content/browser/speech/speech_recognizer_unittest.cc

Index: content/browser/speech/speech_recognizer_unittest.cc
diff --git a/content/browser/speech/speech_recognizer_unittest.cc b/content/browser/speech/speech_recognizer_unittest.cc
index 25bbe22b4caf42df3b1c09a0c7562adaa4256c32..8119ef3d397a4dfa9e928a50724409dfbf0a9d52 100644
--- a/content/browser/speech/speech_recognizer_unittest.cc
+++ b/content/browser/speech/speech_recognizer_unittest.cc
@@ -4,8 +4,8 @@
 
 #include <vector>
 
-#include "content/browser/browser_thread.h"
 #include "content/browser/speech/speech_recognizer.h"
+#include "content/test/test_browser_thread.h"
 #include "content/test/test_url_fetcher_factory.h"
 #include "media/audio/test_audio_input_controller_factory.h"
 #include "net/base/net_errors.h"
@@ -106,7 +106,7 @@ class SpeechRecognizerTest : public SpeechRecognizerDelegate,
 
  protected:
   MessageLoopForIO message_loop_;
-  BrowserThread io_thread_;
+  content::TestBrowserThread io_thread_;
   scoped_refptr<SpeechRecognizer> recognizer_;
   bool recording_complete_;
   bool recognition_complete_;